Low gradient prosthetic heart valve

Abstract

A low pressure gradient prosthetic heart valve for implant in a human. The valve includes a support frame with undulating inflow cusps and outflow commissure posts to which flexible leaflets attach and coapt in a flow area. The commissure posts angle outward in a neutral state to widen the outflow orifice area. Also, the leaflets are designed to fit within the support frame and expand outward in a valve open state without creating a shelf or belly that would restrict flow.

What is claimed is: 
     
       1. A low pressure gradient prosthetic heart valve, comprising:
 a support frame having a leaflet attachment edge with an undulating shape defined by alternating arcuate inflow cusp regions on an inflow end and arcuate outflow commissure regions on an outflow end, wherein the arcuate cusp regions have large radii of curvatures relative to the arcuate commissure regions so that the commissure regions commence at adjacent relatively straight sections leading up to an arcuate commissure tip, the, the support frame, in a relaxed state, circumscribing a flow volume having a central axis, the flow volume having a maximum flow orifice area perpendicular to the central axis limited by the inflow end of the support frame; 
 a suture-permeable sewing ring surrounding the cusp regions that provides a structural anchor to the surrounding anatomy at an inflow end of the support frame, wherein the commissure regions are cantilevered toward an outflow direction from the cusp regions when anchored to the surrounding anatomy such that the commissure tips may flex radially in and out; and 
 a plurality of flexible leaflets attached to the support frame and extending inward toward the axis, each leaflet having an arcuate cusp edge that conforms to a corresponding support frame cusp region and attaches therealong between adjacent commissure regions, and a free edge that coapts with the free edges of the other leaflets to provide one way flow through the valve, the arcuate cusp edges attaching along an undulating line that follows the arcuate cusp regions and along the relatively straight sections of the commissure regions, and the commissure tips may flex in and out from forces associated with fluid pressures on the flexible leaflets, 
 wherein when the valve opens the free edges of the leaflets move outward toward the support frame from fluid flow in an outflow direction and corresponding fluid pressures, and wherein each cantilevered commissure region of the support frame in its relaxed state is angled radially outward so as to provide an outflow orifice area greater than the maximum flow orifice area and induce laminar flow through the valve. 
 
     
     
       2. The heart valve of  claim 1 , wherein the radially outward angle made by each commissure region is α=4±3°. 
     
     
       3. The heart valve of  claim 1 , wherein the inflow cusp regions of the support frame define an inflow plane having an inflow diameter Φ i  circumscribed by the nadirs of the cusp regions, and the commissure regions of the support frame have an axial height H from the inflow plane to their commissure tips that satisfies the following relationship: 
       
         
           
             
               
                 H 
                 
                   Φ 
                   i 
                 
               
               = 
               
                 0.5 
                 ± 
                 
                   .1 
                   . 
                 
               
             
           
         
       
     
     
       4. The heart valve of  claim 3 , wherein the heart valve leaflets have a coaptation point along the central axis where all three leaflets meet upon valve closing, and a coaptation height h from the inflow plane to the coaptation point that satisfies the following relationship: 
       
         
           
             
               
                 h 
                 H 
               
               = 
               
                 0.7 
                 ± 
                 
                   .1 
                   . 
                 
               
             
           
         
       
     
     
       5. The heart valve of  claim 1 , wherein the support frame is formed as a continuous piece of Nitinol with no breaks or crimp. 
     
     
       6. The heart valve of  claim 5 , wherein the commissure regions of the support frame each include an upstanding bar and a series of through holes therein that provide anchor points for other elements of the heart valve. 
     
     
       7. The heart valve of  claim 1 , wherein each leaflet has a size and is attached to the corresponding support frame cusp region such that when the valve opens the leaflets spread outward to provide an outflow orifice area that is no less than the maximum flow orifice area. 
     
     
       8. The heart valve of  claim 1 , wherein each leaflet has opposed attachment tabs disposed between its arcuate cusp edge and its free edge, the leaflet having a central area subject to stress when secured within a surrounding heart valve support frame. 
     
     
       9. A low pressure gradient prosthetic heart valve, comprising:
 a support frame having a leaflet attachment edge with an undulating shape defined by alternating arcuate inflow cusp regions on an inflow end and arcuate outflow commissure regions on an outflow end, wherein the arcuate cusp regions have large radii of curvatures relative to the arcuate commissure regions so that the commissure regions commence at adjacent relatively straight sections leading up to an arcuate commissure tip, the commissure regions being cantilevered from the cusp regions such that the commissure tips flex in and out during use, the support frame circumscribing a flow volume having a central axis, the flow volume having a maximum flow orifice area perpendicular to the central axis limited by the inflow end of the support frame; 
 a plurality of flexible leaflets attached to the support frame and extending inward toward the axis, each leaflet having an arcuate cusp edge that conforms to a corresponding support frame cusp region and attaches therealong between adjacent commissure regions, and a free edge that coapts with the free edges of the other leaflets to provide one way flow through the valve, wherein each leaflet is symmetric about a central midplane that bisects the free edge and arcuate cusp edge, and the arcuate cusp edge of each leaflet is defined by a complex curve of multiple radii, the cusp edges of the leaflets attaching along an undulating line that follows the arcuate cusp regions and along the relatively straight sections of the commissure regions, 
 wherein when the valve opens the free edges of the leaflets move outward toward the flow volume described by the support frame from fluid flow in an outflow direction and corresponding fluid pressures, and wherein each leaflet has a size and is attached to the corresponding support frame cusp region such that when the valve opens the leaflets spread outward to provide an outflow orifice area that is no less than the maximum flow orifice area. 
 
     
     
       10. The heart valve of  claim 9 , wherein the support frame has a relaxed state and each commissure region of the relaxed support frame is angled radially outward so as to provide an outflow orifice area greater than the maximum flow orifice area and induce laminar flow through the valve. 
     
     
       11. The heart valve of  claim 9 , wherein the inflow cusp regions of the support frame reside in an inflow plane within which is defined an inflow diameter Φ i  circumscribed by the nadirs of the cusp regions, and the commissure regions of the support frame have an axial height H from the inflow plane to their commissure tips that satisfies the following relationship: 
       
         
           
             
               
                 H 
                 
                   Φ 
                   i 
                 
               
               = 
               
                 0.5 
                 ± 
                 
                   .1 
                   . 
                 
               
             
           
         
       
     
     
       12. The heart valve of  claim 11 , wherein the heart valve leaflets have a coaptation point along the central axis where all three leaflets meet upon valve closing, and a coaptation height h from the inflow plane to the coaptation point that satisfies the following relationship: 
       
         
           
             
               
                 h 
                 H 
               
               = 
               
                 0.7 
                 ± 
                 
                   .1 
                   . 
                 
               
             
           
         
       
     
     
       13. The heart valve of  claim 11 , wherein the support frame is formed as a continuous piece of Nitinol with no breaks or crimp. 
     
     
       14. The heart valve of  claim 13 , wherein the commissure regions of the support frame each include an upstanding bar and a series of through holes therein that provide anchor points for other elements of the heart valve. 
     
     
       15. The heart valve of  claim 9 , wherein each leaflet has opposed attachment tabs between its cusp edge and free edge, the leaflet having a central area subject to stress when secured within a surrounding heart valve support frame. 
     
     
       16. The heart valve of  claim 15 , wherein the free edge of each leaflet diverges above a straight line drawn between the side tabs to form a supplemental strip of leaflet material that gradually widens as it progresses inward from the tabs until it forms a plateau for a majority of its length, and then rapidly widens in converging curves that lead to an apex on the vertical midplane. 
     
     
       17. The heart valve of  claim 15 , wherein the free edge of each leaflet diverges above a straight line drawn between the side tabs to form a supplemental strip of leaflet material shaped generally as a triangle with an apex on the vertical midplane. 
     
     
       18. The heart valve of  claim 15 , wherein each leaflet is cut from bovine pericardium. 
     
     
       19. The heart valve of  claim 10 , wherein the radially outward angle made by each commissure region is α=4±3°. 
     
     
       20. The heart valve of  claim 9 , wherein the complex curve has its smallest radius on the central midplane that gradually increases on both sides away from the central plane, reaches a maximum at about 45° angle from the central axis, and then gradually decreases to outer extents of the arcuate cusp edge. 
     
     
       21. The heart valve of  claim 1 , wherein each leaflet is symmetric about a central midplane that bisects the free edge and arcuate cusp edge, and the arcuate cusp edge of each leaflet is defined by a complex curve of multiple radii. 
     
     
       22. The heart valve of  claim 21 , wherein the complex curve has its smallest radius on the central midplane that gradually increases on both sides away from the central plane, reaches a maximum at about 45° angle from the central axis, and then gradually decreases to outer extents of the arcuate cusp edge.